In senile dementia, acetylcholine in a brain is lacking so that an acetylcholinesterase-inhibiting agent has been studied. For example, as an agent for curing dementia, there have been disclosed 1-benzyl-4-[(5,6-dimethoxy-1-indanon)-2-yl]methylpiperidine, etc. in Japanese Provisional Patent Publication No. 79151/1989 and 1-benzyl-4-[2-(4pyrrolidinobenzoyl)ethyl]piperidine, etc. in Japanese Provisional Patent Publication No. 173867/1991 (U.S. Pat. No. 5,177,087). However, senile dementia is generally accompanied with symptoms such as depression, lowering of volition, etc. so that various symptoms of senile dementia cannot be ameliorated sufficiently only by an acetylcholinesterase-inhibiting agent. On the other hand, depression is related to monoamine (noradrenaline, serotonin), and as an antidepressant having an A type monoamine oxidase-inhibiting activity, there has been known, for example, 4-(4-cyanoanilino)-5,6-dihydro-7H-cyclopenta[d]pyrimidine as disclosed in Japanese Provisional Patent Publication No. 203072/1982 (U.S. Pat. No. 4,450,162).
The present inventors have studied for many years in order to develop a medicine having both of a selective acetylcholinesterase-inhibiting activity and a selective A type monoamine oxidase-inhibiting activity and therefore having a further improved curing effect as an agent for curing senile dementia, and consequently found that a pyrimidine derivative having a specific structure with selective inhibiting activities to both enzymes, to accomplish the present invention.